Conventionally, in order to reduce electric power steering apparatuses in size, motor control units (MCUs) have been proposed that integrate a control unit and an electric motor.
In some of these MCUs, the control unit is disposed so as to be coaxial to an output shaft of the electric motor, but it is necessary to plan the construction carefully, and the techniques shown in Patent Literature 1 and 2 have been proposed, for example.
In the control unit of the above MCUs, a controlling circuit board onto which a central processing unit (CPU) is mounted, power modules (PMs) that constitute an inverter circuit for supplying electric power to a winding of the electric motor, heatsinks, a connector assembly, etc., are disposed, and ways must be found to connect them electrically and structurally.
In Patent Literature 1, in particular, PMs that supply electric power to each of three phases are arranged distributively, capacitors, which are large parts for suppressing electric power supply pulsation, are disposed in spaces therebetween, and in electrical wiring for the PMs and the capacitors, terminals that extend upward together are connected to busbars.
In Patent Literature 2, pairs of PMs are lined up in parallel for two three-phase inverters, and an attempt is made to reduce size compared to Patent Literature 1 by mounting the capacitors transversely.